It has been known by the state of the art various ink printing devices using several printing heads each containing several ejection nozzles. These nozzles may be arranged on one line and be spaced apart at a substantially constant distance. The use of the multi-nozzle printing heads allows to effectively increase the printing surface in one single passage, thus improving the printing rate. Meanwhile, in this case, the distance between the ejection nozzles conditions the lateral printing resolution, i.e., the distance between two points, in the direction perpendicular to the travelling direction of the printing heads.
However, it is essential to be able to make this lateral resolution vary, while maintaining it constant from one nozzle to the next on one same printing head. In fact, the quality of a deposit achieved by ink jet printing partially depends on the chemical-physical properties of the ejected fluid. The lateral resolution should thus be able to vary from one printing head to another depending on the fluid it contains. Moreover, for one same printing head containing a specific fluid, and for printing several layers, it is usually necessary to modify the properties of said layers by modifying the distance between two adjacent lateral deposits from one layer to another.
It is thus advantageous to be able to rapidly modify the lateral printing resolution with respect to the travelling direction while producing.
It has been known from the state of the art several solutions to reduce the lateral resolution.
The first consists in tilting each printing head with respect to the producing direction so as to reduce the distance between two printed points in the direction perpendicular to the producing direction. Meanwhile, an angle is usually fixed mechanically, and if need be modified manually for each printing head. Yet, within the framework of industrial manufacturing when one wishes to deposit one same fluid but in different conditions depending on the layer to print, it is necessary to be able to modify the angle of the head rapidly and precisely during use, which proves to be impossible if a manual intervention is necessary.
An alternative solution consists in placing several printing head behind each other by shifting them with respect to one another so as to divide the lateral resolution by the number of heads present. The main issue of this solution is that, to obtain a constant lateral resolution, the resolution possibilities can only be sub-multiples of the distance between the nozzles.
Furthermore, once these printing heads fixed with respect to each other, it becomes impossible to print points with a constant lateral resolution on the entire printing width if the user makes the orientation angle of this head group vary according to the travelling direction without modifying the relative positioning of the printing heads with respect to one another.
The object of the present invention is to compensate the drawbacks and limitations of the aforementioned state of the art. In this regard, the invention relates to a printing head holder making it possible to improve the precision and the properties of deposits of a plurality of fluids.